Manchester United and FC Porto advanced to the quarterfinals of the Champions League on Wednesday with dramatic, VAR-inspired winning penalties. How did the video assistant referee system do?

1. Kimpembe's handball in PSG's 3-1 loss to Man United

Diogo Dalot's shot struck PSG defender Presnel Kimpembe, who had jumped and turned his back make himself bigger. Referee Damir Skomina knew the ball had come off Kimpembe and so pointed for the corner, but VAR instructed the official to take a second look at his pitchside monitor. After what seemed like an interminable delay the spot kick was awarded and Marcus Rashford duly sent United through.

Many will feel there was no deliberate act on Kimpembe's part, and he did not appear to move his arm toward the ball, but this decision is consistent with handball penalties awarded at the 2018 World Cup. If the arm wasn't tucked away, VAR would instigate a review for handball; every one resulted in a penalty.

Was this a clear and obvious error? Skomina, though he needed many reviews, came to that opinion and that is the only one that counts. It's very possible he did not even know the ball had hit the player's arm before the review. Would this be given in the Premier League next season? Probably not, but FIFA and UEFA appear to have a lower burden of proof for handball.

Meanwhile, ex-Premier League referees appear to be split on the Kimpembe decision: Peter Walton said it was a definite penalty and Mark Halsey insisted VAR should never have got involved.

The International Football Association Board (IFAB) publishes new definitions for handball on Friday, though so far we are led to believe this will only cover instances where an attacking player is involved. As such, we may still be left with an ambiguous law for defenders.

2. Porto's extra time penalty in win over Roma

This decision was far less contentious. Alessandro Florenzi tugged back Fernando just as the Porto player looked destined to latch on to Maxi Pereira's low shot across the face of the goal. No penalty was given by referee Cuneyt Cakir at the time, but on initial TV replays it seemed inevitable that VAR would call for a review.

Offside was checked, but as we have seen with recent examples involving Salif Sane and Harry Kane, a player can be in an offside position and still win a spot kick. It mattered not, because Aleksandar Kolarov was marginally playing Fernando onside anyway. There was only ever going to be one outcome as Cakir left his screen and pointed to the spot. Alex Telles converted and Porto went through.

There was yet more controversy late on, though, when Roma's Patrik Schick went down in the corner of the box as he was chased by Moussa Marega. Though VAR initiated an upstairs review, he did not ask Cakir to view it pitchside and said play should continue. That was surprising, as it did look like Marega may have clipped the heels of Schick. It was very similar to the penalty awarded via VAR to Iceland's Alfred Finnbogason following a foul by Nigeria's Tyronne Ebuehi at the World Cup.